The correspondence theory of truth is one of the most venerable philosophical theses. Yet it was known almost from the beginning to entail the antinomy of the liar. This antinomy affects any use of the word “true,” not only the use which the correspondence theorist intends. A definition of truth for formalized languages which avoids the antinomy was not formulated before 1931. Tarski's proposal of that year uses an ingenious device. His definition concerns the truth or falsity of the sentences of one language, the object language, but it is given in a different language, the metalanguage. Adapting this definition to natural languages poses some problems, but let us assume they do not exist. Then we may freely apply the word “true” even to sentences of natural languages. We need have no fear of getting involved in antinomies. The use of the word “true” has been rehabilitated. But what about the correspondence theory? Has it too been rehabilitated? Many philosophers claim it has, in particular Karl Popper and his followers. But whether this is so depends of course on what exactly the correspondence theory asserts.

This article is primarily a study of the group selection controversy, with special emphasis on the period from 1962 to the present, and the rise of inclusive fitness theory. Interest is focused on the relations between individual fitness theory and other fitness theories and on the methodological imperatives used in the controversy over the status of these theories. An appendix formalizes the notion of “assertive part” which is used in the informal discussion of the methodological imperatives elicited from the controversy.

These days ‘evolution’ is usually defined as any change in the relative frequencies of genes in a population over time. This definition and some obvious alternatives are examined and rejected. The criticism of these definitions points out the need for a more holistic analysis of genotypes. I attempt such analysis by introducing measures of similarity of whole genotypes and then by grouping genotypes into similarity classes. Three sorts of measures of similarity are examined: a measure of structural similarity, a measure of functional similarity and one of relational or historical similarity. The functional approach is shown to be superior and a definition of ‘evolution’ is suggested.

Theoretical simplicity is difficult to characterize, and evidently can depend upon a number of distinct factors. One such desirable characteristic is that the laws of a theory have relatively few “counterinstances” whose accommodation requires the invocation of a ceteris paribus condition and ancillary explanation. It is argued that, when one theory is reduced to another, such that the laws of the second govern the behavior of the parts of the entities in the domain of the first, there is a characteristic gain in simplicity of the sort mentioned: while I see no way of quantitatively measuring the “amount” of defeasibility of the laws of a theory, microreduction can be shown to decrease that “amount.”

The Relevance Criterion of confirmation gained prominence as the underlying principle of the class-size approach (CSA) to Hempel's paradoxes of confirmation. The CSA, however, yields counter-intuitive results for (c) instances, and this failing cast serious doubt on the acceptability of the Relevance Criterion. In this paper an attempt is made to rescue the Relevance Criterion from this embarrassment. This is done by incorporating that criterion into a new resolution of the paradoxes, a resolution based on a theory of selective confirmation and a distinction between mere confirmation in principle and evaluative confirmation (E-confirmation).

The distinction between discovery and justification is ambiguous. This obscures the debate over a logic of discovery. For the debate presupposes the distinction. Real discoveries are well established. What is well established is justified. The proper distinctions are three: initial thinking, plausibility, and acceptability. Logic is not essential to initial thinking. We do not need good supporting reasons to initially think of an hypothesis. Initial thoughts need be neither plausible nor acceptable. Logic is essential, as Hanson noted, to both plausibility and acceptability. An hypothesis needs good supporting reasons to be either plausible or acceptable. Such reasons need not be relative to the particular scientific theory undergoing test at the time. There is no fundamental difference between reasons relevant to plausibility and acceptability. The difference is one of degree. Acceptability requires more than plausibility.

In a recent article [4], Fred I. Dretske has proposed a new analysis of natural laws. Dretske rejects the more or less standard view which says that laws are universal truths with a special function or status in science. As an alternative account, he suggests that laws are expressed by singular statements describing the relationship between universal properties and magnitudes: the statement

(1) It is a law that F's are G's3.

is to be analysed as

(2) F-ness ↦ G-ness.

I shall argue, however, that Dretske's reasons for rejecting the standard account are not conclusive. Moreover, his own proposal seems to be either inadequate or reducible to that version of the standard account which takes laws to be nomically necessary generalizations.

While the use of so-called idealizations in science has been widely recognized for many years, the philosophical problems that arise from this use have received relatively little attention. Even a cursory reading of the philosophical literature devoted to these problems ([1]; [2]; [4], pp. 160–171; [5]; [7], pp. 54–63) reveals that the following questions remain unanswered: In general, what, if any, are the distinguishing characteristics of idealizations? More specifically, do idealizations have any distinguishing syntactic or semantic characteristics? In addition to these questions there exist the following pragmatic questions, questions relating to the ways in which idealizations are used in science: How are idealizations used in explanations? (see [2]). Do these explanations have any peculiar characteristics—characteristics not shared by deductive-nomological (D-N) explanations? If we assume that (at least some types of) idealizations are false (or contain false components) or “do not obtain,” how is it that they can have any explanatory power? (see [7], p. 58). Further, there are questions of more general philosophic concern. How do the problems of idealizations relate to those of simplicity, for an idealization seems to be, in some sense, a type of simplification? How do the problems of ideal laws and theories relate to the general problems of scientific laws and theories?

In “Laws of Nature” [1] I argued that natural laws are not universal truths. Laws have properties that enable them to function in a special way. Since universal truths do not have these properties, they cannot be promoted to the status of laws by assigning them this function, by using them in the way laws are typically used. To suppose that we could effect this transformation by the way we used a generalization is like supposing that we could make thumb tacks into garden hoses by using them to water flowers. It will not work. Thumb tacks lack the requisite structure. Hence, they cannot be used in the way garden hoses are normally used. And universal truths lack the properties that would enable them to function, and thereby qualify, as laws of nature.

The relation that holds between two singular sentences just if one of them can figure in an acceptable deductive nomological (DN) explanation of the other is not symmetric. As Sylvain Bromberger ([1]) pointed out some years ago, a sentence giving the height of a flagpole can figure in a DN explanation of a sentence specifying the length of the flagpole's shadow, but interchanging the explanans and the explanandum does not result in an explanation even though it may result in a valid argument. Recently Evan Jobe ([2]) has offered an ingenious account of such asymmetries, one which if successful would permit their characterization entirely within the framework of the DN model. The purpose of this note is to show that despite its attractiveness Jobe's idea will not work.

Extensive measurement is called weak if the axioms allow two objects to have the same scale value without being indifferent with respect to the order. Necessary and/or sufficient conditions for such representations are given. The Archimedean and the non-Archimedean case are dealt with separately.

Germund Hesslow has argued recently [2] that a probabilistic theory of causality as advocated by Patrick Suppes [4] has two problems that a deterministic theory avoids. In this paper, I argue that Suppes' probabilistic causal calculus is free of each of these problems and, moreover, that several broader issues raised by Hesslow's discussion tend to support a probabilistic conception of causes.

Beauregard ([1], p. 488) claims that Bowman and I were mistaken in saying that “… if the empirical predictions of the Special Theory regarding clock transport are correct, [then] a slow transport definition of simultaneity can be constructed that is logically independent of any signal definition, but is in fact equivalent to the standard signal definition” ([2], p. 131) His objection is not to the empirical concordance of the two criteria, but to the claim that the two are logically independent. His argument is that we fail to take account of Winnie's Passage Time Principle ([4], p. 228), and that if due account is taken of this principle, then “the concordance between the two criteria is logically guaranteed by the synchrony-free factual core of the STR” ([1], p. 488). However, one cannot show that A is not logically independent of B by showing that it is not independent of B and C. Hence, Beauregard's argument fails against the quoted passage.

In The Structure of Scientific Inference ([2]), Mary Hesse has argued for a realist interpretation of science. Her realism, however, is not to be understood in the context of the traditional realist/instrumentalist debate within the philosophy of science. That debate focused on the question of whether or not science did anything other than systematize the empirical data given in our experience. The traditional realist answered “yes” and most frequently described the theoretical statements of science, not only as true, but also as providing descriptions of the world. The instrumentalist on the other hand answered “no” and ascribed no descriptive force to the theoretical statements of science. However, according to Hesse, neither party in the contemporary realism debate assumes the notion of an empirical given. Consequently, the present dispute must be understood as taking place on a level which is logically prior to its predecessor.

In a recent note ([3]) Roger Carlson presented a rather negative appraisal of my treatment of the logic of Fisherian significance testing in [10]. The main issue between us involves Carlson's thesis that, within the limits set by Fisher, standard significance tests are valuable tools of data analysis as they stand, i.e., without modification of the structure of the reasoning they employ. Call this the adequacy thesis. In my paper I argued that (i) the pattern of reasoning employed by tests of significance needs to be justified in spite of its unquestioned acceptance by most researchers, (ii) The best justification offered to date—by R. A. Fisher—is seriously defective. Therefore (iii) the adequacy thesis is not justified. I proposed some alterations of the pattern of reasoning employed by tests of significance and argued that they guarantee that tests are adequate epistemological tools.

In a recent paper, Michael Levin argues that both statements reporting causal relations and causal explanatory statements are extensional. We show that his argument for the extensionality of causal explanatory statements fails to establish that conclusion. His claim that certain ‘because’ statements are elliptical for statements of what he terms the ‘causal explanatory’ form is unsubstantiated. The argument for the referential transparency of the allegedly explanatory form, regardless of whether it is a distinct explanatory form, fails because of scope problems. Finally, we argue that the apparent referential opacity of explanations, the attribution of certain kinds of properties to explanations, and our satisfaction with explanations in what appear to be disparate forms are best accounted for, not by the assumption of ellipticality of statements in various forms for statements in some inherently explanatory form, but rather by an account of explanation as a speech act, the success or failure of which may be affected by which of several co-referring expressions is employed.

In recent years there has been a rebirth of interest in the philosophy of Pierre Duhem. Although I applaud the spirit of this movement, one finds the critics of Duhem frequently lacking in a basic understanding of Duhem's tenets, sometimes to the extent that one doubts a familiarity with the Duhemian text. One of the few papers which is designed to remedy this state of affairs is that of Philip Quinn entitled “What Duhem Really Meant.” Quinn is to be applauded for his meticulous and rigorous exegetical work on the Duhemian text. Unfortunately, Quinn's characterization of the logical relations of two of the central Duhemian theses is erroneous. I shall endeavor to correct these errors in this paper.

Limitations of space dictate that we confine ourselves to Miss Stern's most salient comments. First, a preliminary point. Miss Stern says “Levin offers no argument” for why “e happened because of c” implicitly contains an explanatory description, while “c caused e” does not. But surely the remark ([1], 273) that we often know that c caused e without knowing why c caused e is just such an argument. Our linguistic intuition suggests that we use the first locution in this case; Miss Stern's evidently does not. Cases of non-diagnostic causal ascriptions do exist, and even ordinary language must provide for them; how it does so is a verbal dispute about English.

In [2] I have presented a sketch of a principle which I suggested was powerful enough to enable us with its aid to solve a number of well known problems in the philosophy of science. James Moor in [1] expresses the opinion that my principle is too strong so as to be destructive and proposes instead a considerably watered down alternative which may be used for constructive purposes only. I shall deal here with his two major objections only and show that on a careful enough analysis it becomes evident that he has not raised any difficulties for my principle.

In pursuing philosophical enquiries in the foundations of physics, I have found myself operating with a concept of explanation which has a quite different logical syntax from the concept which Hempel has explicated. I suspect that the concept of explanation I operate with is not especially idiosyncratic, is not fully captured in the existing philosophical literature (though I am open to correction here), and that it may be the more appropriate concept if we are to consider explanation as the goal of physics. I therefore propose to give here a short account of the structure of this alternative concept of explanation.